Retort furnace



A- MUSSO RETORT FURNACE Jan. 19, 1932.

W INVEN Filed March 20, 1929 uwmm i N. m3 @N g Q TN 3 mm 5 mm #3ATTORNEY-5 Jan. 19, 1932. A. Musso RETORT FURNACE Filed March 20, 1929 3Sheets-Sheet 2 INVENTOR 9' ATTORNEY A. MUSSO RETORT FURNACE Jan. 19,1932.

Filed March 20, 1929 3 Sheets-Sheet 3 INVENTOR Y ATTORN EYS PatentedJan. 19, 1932 UNITED STATES PATENT OFFICE ALFRED MUSSO, OF EAST ORANGE,NEW JERSEY, ASSIGNOR 0F ONE-HALF TO WILLIAM P. DEPPE, OF NEW YORK, N. Y.

RETOR'I FURNACE Application filed March 20, 1929. Serial No. 348,379.

, This invention relates to furnaces and proc esses practised inconnection therewith.

One object of the invention is to provide a device of the characterdescribed, including improved means for heating a chamber from theoutside thereof.

Another object of the invention is to provide an improved device of theclass specified including an eXterio-rly heated chamber, the charge inwhich, at any point of the chamber, is subject to heating by conductionand radiation at substantially the same temperature, although thedifi'erent points of the chamber may be at the same .or at differenttemperatures as predetermined.

Another object of the invention is the provision of a device of thenature set forth hav ing improved means for movement through a furnaceor retort chamber of the charge that is being heat treated therein.

Another object of the invention is to furnish a device of the typementioned having a heating chamber which is divided into a plurality ofcompartments by improved means that restricts the flow of gases from oneto another of the compartments and coacts for movement of the charge inthe chamber through the successive compartments.

Another "object of the invention is to construct a device of the speciesalluded to, having a heating chamber through which is passed the chargethat is being treated, which device includes improved means forseparately removing from the chamber the gases in diflerent sectionsthereof. 1

Still another object of the invention is to provide a device of thecharacter described having improved means to create a partial vacuum ina retort and to exhaust all gases generated inthe retort chamber instages ac-.

cording to predetermined temperature or temperatures.

Still a further object of the invention is the provision of a heatingdevice operating un der a co-ordinated temperature and pressuregradients, and an improved control to automatically maintain therequisitetemperatore-pressure relationship.

Other objects of the invention are the pro vision of an improved deviceof the nature set forth wherein a temperature gradient is maintained inan improved manner in the heating chamber; and wherein heat is imparted'to the chamber without causing oxidation of the same; and wherein thegases generated are removed'in one or more stages from the heatingchamber without removal of the nongaseous ingredients that are beingtreated regardless of how fine the same may be; and wherein an. improveddevice controls and mixes the supply of air and gas.

Still further objects of the invention are to provide an improvedprocess for heat treat ing a charge by conduction and radiation atopposite sides but at predetermined temperatures without contact withthe products of combustion; also to provide an improved system ofheating the charge by radiation under reduced pressure or partialvacuum.

Still further objects of the invention are the provision of an improvedprocess for the heat treatment of materials, wherein the factors oftemperature, pressure, and reaction velocity are co-ordinated forequilibrium conditions; and an improved apparatus for carrying out thisprocess. v

This invention is particularly intended for use in my process of lowtemperature reduction of metals, Serial No. 325,713, filed December13th, 1928, and aims to provide an eflicient apparatus therefor.

It must be kept clearly in mind by those skilled in the art, that sincethe process, more specifically disclosed in copending processapplication, Serial No. 325,713, filed December 13th, 1928, to whichthis apparatus is primarily directed includes a co-ordination oftemperatures, pressures, and particular retort atmospheric conditionsconducive to the chemical reactions involved, under the limitations andphysical forces necessary for the effective practice of the process,that the combinations of the structural features of the apparatus intheir physical and functional relationshipsmust also be co-ordinated ina corresponding sense; hence the apparatus illustrated involves someunusual interrelations which have never been heretofore devised.

It must be particularly noted that the apparatus suitable for this newprocess, illustrated in this disclosure employs for the first time, theprinciple of reducing iron ores with any kinds of coal in massproduction conditions, in an air-tight retort, wherein is included themeans for mechanically accelerating the substantially complete reductionof the materials being treated by means of solid carbon reduction. Thegaseous reactions are substantially eliminated, through the continuousforcible exhaustion of all gases being liberated and formed in theprocess, at temperatures below the fusion points of material whicheliminates melting, agglomeration, or sintering. The volatileconstituents of coal and the maximum amount of CO available,continuously and forcibly withdrawn from the reducing ambient in thisprocess, causes the novel result of the production of suflicient fuelgases to operate the system.

In this process, which is primarily devised for mass productionconditions, particularly for the use of any kinds of iron ores, oxides,or carbonates, and any kinds of coal, in order to decrease the time forsubstantially complete reduction of the ores being treated, particularlyiron ores, at lowered temperatures, it is essential to forcibly andcontinuously exhaust all gases in the retort as fast as formed, topractically eliminate the gaseous reaction conditions, and to maintainsubstantially solid carbon reaction, with chiefly CO produced, andlittle or no CO produced, and with lower temperatures permissible in theretort, but high enough to cause substantially complete reduction, and

- yet not high enough to cause fusion, thus eliminating melting,agglomeration, or sintering in the materials being treated. For example,the maximum temperature for reducing iron ores mixed with coal, isapproximately 950 C.

Other objects and advantages of the invention will become apparent asthe specification proceeds.

With the aforesaid objects in view, the invention consists in the novelcombinations and arrangements of parts hereinafter described in theirpreferred embodiments, pointed out in the subjoined claims, andillustrated on the annexed drawings, wherein like parts are designatedby the same reference characters throughout the several views.

In the drawings, which are submitted to show features of the invention,but not to limit the scope of the claims:

Figure 1 is a longitudinal view in vertical section of a deviceembodying the invention.

Fig. 2 is a cross sectional view takenon the line 2-2 of Fig. 1.

Fig. 3 is a similar view taken on line 33 of Fig. 1.

Fig. l is an enlarged fragmentary view of the exhaust pipes and astrainer, shown in Fig. 1.

Fig. 5 is a view in section taken on line 5-5 of Fig. 4.

Fig. 6 is a vertlcal sectional view taken on line 66 of Fig. 1.

Fig. 7 is a view in elevation of a heating means for a retort with partsin section.

Figs. 8 and 9 are sectional views taken on horizontal and verticallines, respectively, on Fig. 7.

Fig. 10 is a view in section of the fuel control and mixing apparatus.

Fig. 11 is a cross sectional view thereof taken on line 1111 of Fig. 10.

Fig. 12 is a diagrammatic view of a coordinated temperature and pressurecontrol.

Fig. 13 is a fragmentary view in vertical section taken on line 13-13 ofFig. 1.

Fig. 14 is a view in vertical section of a modified heating ring andfurnace arrangement.

Fig. 15 is a view in vertical section of a. still further modificationof a heating ring.

Fig. 16 is a vertical sectional view taken on line 16-16 of Fig. 15.

Fig. 17 is a diagrammatic view of a modified arrangement of the heatingrings with respect tothe work or retort furnace.

Figs. 18 and 20 are fragmentary views in longitudinal vertical sectionof heating chambers with modified partition constructions.

Figs. 19 and 21 are transverse sectional views taken on the lines 1919and 21 21 of the devices shown in Figs. 18 and 20, respectively.

The advantages of the invention as here outlined are best realized whenall of its features and instrumentalities are combined in one and thesame structures, but, useful devices may be produced embodying less thanthe whole.

It will be obvious to those skilled in the art to which this inventionappertains, upon becoming conversant with the features thereof, that thesame may be incorporated in several different constructions. Theaccompanying drawings, therefore, are submitted merely as showing thepreferred exemplification of the invention. The underlying scientifictheory, as well as the objects of the invention will determine itsscope, as it is possible to produce other devices which will accomplishsubstantially the objects of the reaction is a function of the ratio ofthe pressure to the temperature. By my improved process, this functiongoverns the reaction throughout, so that the reaction velocities areuniformly accelerated or retarded, as the case may be. A reaction whosevelocity is a practice this can be but approximated in stages ashereinafter indicated.

As a specific example of the subject matter set forth in the precedingparagraph, I may mention that .in the process of mineral reduction, forinstance, in that of ferric oxide J (Fe O bymeans ofthe fixed amorphouscarbon of coal, we have two phases, -viz., solid iron (Fe) and gaseouscarbon monoxide (CO) coexistent at all times, while the carbon (C) andthe oxygen (0) which form the C0 are combining under equilibrium con--ditions. To better explain the fundamental vtheory, in the case of ironreduction, I will set forth the chemical equation of the reduction,which-is x FBzbg-I-SCQZFB-l-iiCO This equation is to'be considered asthe eiiect of the two simultaneous equilibria, viz.

2Fez0z24Fe-k30z (dissociation of ferric oxide) Oz+2C? 2CO (formation ofcarbon monoxide).

Ofthe two simultaneous equilibria, the first one tends to liberates theiron contained in combination with the'oxygen in the ferric, oxide,while the second equilibrium tends to eliminate the oxygen as such fromthe system byconverting it to carbonmonoxide. The

completion of the reaction, according to well' established principles ofphysical chemistry, is brought about by the elimination of the gaseousphase 00 from the system, by the exhaustion of the gases from the retortchamber as fast asthey are generated. In order to further avoid thepossibility of a reversible "reaction, an excess of carbon is suppliedand always present, conforming thus withthe well known principle ofmobile equilibrium and the law of mass action. This brief discussion onthe basic principles of my invention as applied to iron reduction, isgeneral and applicable to all kinds of reversible reactions which canbecaused to occur in my apparatus: In all reactions, such as the reductionof iron above referred to, where gas is generated, and where the naturaltendency would therefore be toward an increase of the total pressure ofthe system, any reduction of the total pressure, will favor thereaction.

on the other hand, there is for each pressure a corresponding .definitetemperature, and vice versa. Thisjresults in thetheory that in anysystem contemplated by my inven- Tho'completeness of the 'reac- Q tion,where, during the course of a reaction, temperatures and pressures mustbe made to vary, in order to attain a completion of the equilibriainvolved, the course of the reaction is a function of the ratios of thepressure to the temperature. And this is the 'statement of the generalprocess provided by my 'invention.

While for: the reduction of iron ore, the temperature is increasedrandthe pressure dc creased, the invention is equally applicable tosuchreactions as require av decrease in temperature and simultaneous 1increase in pressure; or an increase or decrease of both temperature andpressure; or where1n-one of these factors remains constant while theother alone changes, although 1t is contemplated that the bestconditions are obtained by causing both temperature and pressure toharmonize for the reaction: in each case, the

rate of the change of these factors,or the rate of change of the ratioof the factors is sub stantially constant, as, forinstance, according toan arithmetic progression. It is preferred that the temperatures andpressures herein be taken onthe absolute scales, although other scalescan also be used.

It is noted that, for certain reactions, successive changes oftemperature and pressure may be such that the difl'ereuce'between theratios is substantially zero.

Referring again to the reduction iron,

the increase-of temperature and decrease of pressure tends to promotethe dissociation of the iron oxide. The decrease of pressure, however,mihtates agamst the formation of the carbon monoxide, but th1s'1scounteracted by several factors, among which are the in-,'

crease of temperature, the natural aflinity of oxygen for carbon, andthe. presence of hydrogen which acts as a catalyst in the formation ofcarbon monoxide. In the last stages of.the reduction, hydrogen isevolved in rather considerable quantities from thev carbonaceous fuelwhich is used in the charge and acts effectively as above stated.

The term charge is intended to denote the ingredients in the'retort atany stage of the reaction, or any materials or articles that maybeadvantageously heat treated in a fur-- nace embodying one or more;featuresof this invention, regardless of whether or not such heattreatment is accompanied by a chemical reaction.

Generally described, the inventionprovides an elongated heating chamber,which may be in themature of a cylindrical retort.

The same is rotatable about its axis, 'Wh-lCh is preferably inclinedwith the horizontal, to cause the charge introduced inthe retort to movetherethrough. The end portions of the retort arev each formed with-aconcentric series of conveyer pockets which rotates with the retort.Coacting with each series of pockets is a circular stationary closuremember so arranged to. permit a lowermost pocket to receive a portion ofthe charge, but to close the filled pocket as it moves upward, andfinally to permit the charge to be removedothrou h an opening in themember with which when the same reaches its uppermost position. Thecharge in the pockets thus acts as a seal and contributes to render theretort air tight. This system of conveyer pockets feeds the charge tobetreated int-o theretort at the upper end of theretort and feeds saidcharge from the retort after treatment at the lower end of the same.Dividing the retort into a plurality of successive compartments aretransverse partitions which are of substantially gas tight construction.These partitions comprise the conveyer features that are provided at theends of the retort, and thus cause the charge to be passed from onecompartment to another. Extending centrally through the retort is astationary shaft that supports the stationary circular members of thepartition conveyer construction. Associated with the shaft are aplurality of pipes communicating individually with'the compartments,whereby the gases in the latter may be exhausted by pumps. A screen mayserve to prevent finely divided ingredients in the retort from enteringthe pipes. A scraping blade or other similar device may keep thestrainer clean. The retort is heated by radiation from the outside bymeans that are disposed between the retort and the wall of the furnace,the intraspace being closed so that air may not leak thereinto.Preferably the said means are in the nature of stationary ringsconcentric with the rotating retort and disposed therealong in spacedrelation to each other; thus transverse sections of the retort aremaintained at the same temperature along the peripheral surface of eachsection, so that the charge lying along the bottom of the retort isuniformly heated from its undersideby conduction and from above byradiation, the latter occurring with high efiiciency due to theexhaustion of the gases from the retort, and the consequent eliminationof any gas film that would otherwise adhere to the interior surfaceofthc retort wall. The said rings may consist of pieces of refractorymaterial calcined with a suitable binder and having considerable voidsto permit passages therethrough of the waste combustion gases, while theoutside of each ring is glazed to render the same gas tight. Premixedgas and air in combining ratio are fed under pressure into each ring,and surface combustion occurs therein. To maintain a temperaturegradient the spacing of the rings may be varied. An automatic controlco-ordinates the temperature and pressure in the retort in the pocketcomes into registry,

" For metallic reduction, an apparatus as above described is preferablyemployed, but for oil shales orsimilar materials, the retort may bemaintained at constant temperature throughout the length thereof, andthe subdivision of theretort into compartments with separate exhaustionof the same may be eliminated.

While the invention contemplates preferably the application of the sameto the re duction of minerals, certain principles thereof are applicableto furnaces of heating chambers of Widely different types where uniformheating is desired, with ,or without the use of a retort, as, forexample, in soaking furnaces; and also to different chemical ormechanical operations, as, for instance, roasting or driving offvolatile constituents in materials other than mentioned, or treatingsubstances under varying conditions of temperature and presthe heat soobtained may be generated in a central heating chamber and directlypassed about the retort or through tubular devices capable of radiatingtheir heat upon'the i'etort. Electrical heating can be employed also,although this may be considered as too expensive for ordinary commercialuse, It suffices that a uniform temperature is obtained for the chargethat is being treated, both by conduction and radiation, and especiallywhen accompanied by a simultaneous rotation of the retort.

The end walls, or partitions, or both may assume different forms,depending, among other factors, upon the partial vacuum that is desiredin the retort, and whether a pressure gradient is maintained in thesame, or whether the" gases are exhausted in separate compartments orstages but at substantially the same pressure.

In the treatment of finely divided materials of any kind, as, forexample, in the reduction of a mineral by a solid fuel, there is a knowninterstitial volume V and a known free volume V in the retort, the ratioof the volumes being a number larger than 1. Now, considering at anyinstant the pressure and temperature, and P being the pressure in theinterstices,

and P the pressure in the heating chamber and because I P1 V =mV P =mP-o1' P2=E which may be even less than one atmosphere. In all cases, thevalue of P is less than if no exhaustion occurred, for then P wouldequal P that is, the pressure in the free space in the retort wouldequal the pressure in the interstices. Since is known can be maintainedconstant, for each condition of temperature in the retort. Theelectrothermal mechanical device disclosed herein renders it possible toautomatically maintain the pressure-temperature ratio. Similarly,because the ratio of the volumes V and V is known or can bepredetermined for any required pressure ratio the temperature tocorrespond to the initial required conditions can be readily obtained.Thus for any 'given conditions, and since the ratio of the volumes V andV is substantially constant throughout the retort, it is always possibleto determine the ratio of the pressure P of the retort chamber to thetemperature T of the same. From the preceding discussion, the value ofthe ratio P /T is obviously a function of the initial condition andtherefore can be predetermined or modified as one of the two terms ofsaid ratio may vary in the course of the reaction.

The rate at which the ingredients that are being treated undergo the'desired change, and more particularly the reaction velocity, as inreduction of a mineral, is fixed by the pressure-temperature ratio,which thus predetermines the time that is required for the completereduction of the mineral. Accordingly, the time during which theingredients are to remain in the retort, and consequently the properrotational speed of the retort may be ascertained. By thus co-ordinating temperature, pressure, and reaction yeloc'ity to assureproper equilibria at various points of the reactions, there resultscontinuous performance with completeness of the reactions 'and purity ofthe metal. With the eliminafurnace, Serial No. 259,406, filed March 6th,

1928. The said device comprises a heating chamber or retort 21, made ofany suitable material consistent with the temperature required. For thecomparatively low temper atures used in my process, the retort may bemade of steel with an inside and outside coating of chromium. For highertemperatures a chrome alloy steel may be found suitable. In general, anymetallic alloy adapted to withstand high temperatures is employed, theuse of metal permitting a more economical transfer of heat through thewall of the retort and also a lighter construction in the mountingthereof.

The retort 21 may be of cylindrical or other form rotatable about itsaxis which makes an angle with the horizontal to move the charge thereinfrom the upper inlet end 22 to the loweroutlet end 23 thereof. Theretort may also be differently arranged, particularly if adiiferentsystem is employed for moving the charge through the rotor.

The retort is mounted in a furnace 24 having an elongated chamber 25 toreceive the same, which chamber is closed by stationary end plates 26,27. The wall of the furnace may beconstructed of refractory brick orother like material and the end plates may be of metal of a heatresisting nature, properly insulated.

The end portions of the retort are enlarged' in diameter at 28, 29, andthe free edges of the same are received in annular recesses in the endplates to form a tight connection. The member. 29 includes an oppositelyprojecting annular flange 31 that engages in a circular recess 32 in thefurnace wall.

. Carried exteriorly by the member 29 is a gear 33, whereby the retortmay be rotated at a predetermined speed by any suitable source of power,such as an electric motor. Suitable idlers, in the nature of pinions,whose teeth mesh with those of the gear 33, may serve to supporttheretort, but this arrangement being readily understood, has not beenshown. At the other end of the retort, a circular band or rail 34 takesabout the same, and rides on idlers 35 to support the retort. Similarband and idlers are prm vided at the center of the retort. To obtainaccess to the idlers, heat insulated plugs 35a maybe used.

The circular spaces within the members 28, 29 are divided by radialwalls35 into a plurality of alined circular series of pockets 37, 38, whichconstitute conveyers. The radial walls terminate at 39 so as to'extendin the general direction of the lengtli' of the retort and also radiallyinward so as to terminate at 40 in spaced relation to the axis thereof.At 39, however, the conveyer pockets are closed by the stationary endplates 26, 27 with which the radial bucket partitions 36 have clearance.Closing all except the uppermost and lowermost pockets of the conveyers37, 38 at their inner edges 40 are circular or substantially cylindricaldrums or closure members 41, 42, respectively, the same being fastenedto or integral with the end plates and are substantially equal indiameter and coaxial with the retort, but fixed with respect thereto,being mounted upon a stationary shaft 43 that extends centrally throughthe retort and is secured at 1ts ends in the hubs 44 of the said endplates. Each of the members or drums 41, 42 has a supporting diskportion 45 through which the shaft passes. At its upper part, the member41 has an opening 46 communicating with a downwardly inclined chute 47passing through the end plate 26, with the lower wall of the chuteextending to the disk 45 to which it may be secured. The lower part ofthe member 41 has an opening 48 in the wall 45 thereof, there being atop entrance member 49 for said opening extending into proximity orfastened to the end plate 26.

The charge in the retort will tend to load: through the opening 48 intoany lowermost pocket of the conveyer 37 and be carried upward with therotation of the retort, about the circular closure member 41 until thepocket comes into registry with the opening 46 permitting the loadtherein to be discharged from the pocket into the chute 47 The member 42at the inlet end of the retort has openings 50, 51 similar to those at48 and 46, re-

spectively, so that charge may be carried from a hopper 52 down a chute53 and thence though the opening 51 into any lowermost pocket of theconveyer 38, after which the charge is carried upward in the pocketabout the member 42 and finally discharged through the opening 50 downan incline 54 into the retort.

The heating chamber or retort 21, is divided into a series ofconsecutive compartments 56 to 59 by-a plurality of transverse walls orpartitions 55 comprising conveyers according to the principle of theconveyers 37 and 38. Each of the said partitions includes a ring plate60 secured to the wall of the retort and having a circular series ofradially extending blades 61 that have free edges 63 and 64, the formerprojecting toward the axis of the retort, and the latter toward theinlet end thereof. The said blades provide a circular series of conveyerpockets 55a concentric with the retort. /losing the said conveyer pocketat the edges 63, 64 thereof are circular closure members 65, each ofwhich includes a disk 66 mounted on the stationary shaft 43 and coactingwith the edges 64. Each of said disks carries a cylindrical drum 67having closure coaction with the edges 63. At the upper part of thedrum, the same has an opening 68 to register with an adjacent conveyerpocket. Now each disk has an inlet opening 69 disposed to one side ofthe vertical plane of the retort, according to the counter-clockwisedirection of rotation of the same, which will cause the charge in theretort to pile toward the right side thereof. If the retort should moveclockwise, the inlet 69 would beat the left side. Thecharge passesthrough an opening 69 into any lowermost pocket of the conveyer 55a, andas the retort rotates, the charge is carried upward over the closuremember or drum 67, until, in the uppermost position of the pocket, thecharge moves throu h the opening 68, down an incline '70 into t e nextsucceeding compartment.

Thus at the inlet and outlet of the retort, and at the partition '55,positive movement of the charge is assured, under conditions thatsubstantially prevent leakage of air, or gas, or both. The finelydivided ingredients of the charge serve to seal theclearance) spaces atthe conveyers. Within the retort the charge may thus be caused to moveat a positive uniform speed through the successive compartments 56 to59, depending upon the speed of rotation of the retort and theconsequent speed of the conveyers.

To obtain further air. tightness of the retort, the chutes 47 and 53 maybe each provided with a plurality of spacedfly valves 71, 72 which aregeared together in any suitable manner for simultaneous movement.

The valves are set so that when one of them is open, the other isclosed, thus avoiding air leakage. The quantity of charge passingthrough a chute at any operation of the valves is determined by thespace between the valves. Since the charge is in finelydividedcondition, practically no air will enter therewith.

Extending along the stationary shaft 43, are a plurality of pipes 73 to76 Which enter the retort at the inlet side thereof, and each of whichcommunicates with one of the c0mpartments 56 to 59 respectively. Theshaft 43 may be grooved longitudinally as at 77 to receive the pipes,thus making for a highly compact construction. At the retort partitions55, sleeves 78 are provided closely receiving the said pipes and havingflanges '79 at the ends. of the sleeves, which may extend to the surfaceof the said pipes and of the shaft. The drums 65 are securely mounted onthe collars, the flanges of which are on opposite sides of the drums.

Externallyof the retort, the pipes communicate individually with exhaustpumps 80 to. 83, that are of any suitable type or size according to thereduction of pressure desired in the retort and in the particular com- Jpartments thereof. By means of this artort. The wall of the retort isspaced from rangement, a pressure gradient can be mainthese areas anysuitable distance consistent tained in the retort, with pressures whichwith economical heatin under-uniform radimay be considerably belowatmospheric,varyation to the retort, an while this space as 'ing fromone to another of the successive shown in the drawings, is preferablycom- 70 compartments 56 to 59. v paratively close, it may besubstantially vin- To preventfinel divided ingredients of creased tomeet all operating conditions. the charge in the retort from being drawnSince the radiating zones are of ring form as .into an exhau pip nySuitable means W 1 above stated, any compartment or transverse known inthe art may be employed, whether section of a compartment is subject touni- 75 electrical or mechanica t0 form temperature all around to impartuniby centrifugal action, or simple screens" 84 f h atin b nd tion andradiation to m y be Used? The e are yl ri al in form the charge in theretort. Since the retort I 110 urround the plp s and extend from isexhausted causing the rapid removal of to end of each compar men They ybe inert gases from along the wall of the retort,

Secured to y shitahlemeahs, e for examthe radiation of heat onthe chargeis imple the flanges 79, and similar flanges 85 proved 7 adjacent to theend Walls Of the P hu Each zone 90 may include a ring- 91 that is thegases exhausted y the 531d P P are set into the wall of the furnace orextends into thoroughly sel'eehede the large Screen the chamber 25thereof as shown. The area, there is Practically he cloggihg'of therings may all be of the same construction,

- SeI'eehS- Furthermore, the .sel'eehs e P being made of a porous massof refractory Sitiohed remotely from t ch g in which is gas tight alongthe outside thereof. bottom ht e y, ahvehvleus Thus arefractory-consisting of pieces 92 of manner, be (imposed t hpp tethercarborundum, zircon, or graphite may be Pe the retort, and efl y usedenclosed in a gas tight refractory wall. Wlth the P p in e eehtml p treo Preferably, the said pieces have been previ- The eeveralscreensmaybe of varymg n ously mixed with a binder, as for'instalice, to Shlt theeempahtmehtsa n P y of -tar, then moulded into ring form, and calscreens y. he d p exterml'ly of each cined at a temperature above thatto which other with the Screen of lehgeh mesh the ring will be subjectedto volatilize all Side: t desired, a p h yl e e to hydrocarbons of thebinder and lea'veastrong automatlcally clean the screens coincident b dyf refratory Th th id with the rotation of the retort. If desired atthesurfaces of the ring can be filled with y Suitable design of h t traps Qtar refractory to provideacomparatively smooth y Scrubbers y be lhehldedm the base. Finally, the outside surfaces of the hhe between the retortand the p p ring are glazed at the base thus formed to P p a pluralityof arms 87 extend-from the may be glazed or permitted to remain unformhf Spaced eyhhdhiealhl'eas rings the surfaces 96 communicatingwith theburner uexternally or internally; More specifically, The cement 99 isintended to reenforce the so they provide a means of indirect heating ofring at the region where the maximum temue g h ga he fast as e provide agas tight surface, but the surface To hl'aee theisheft 43 and thesald'exhahst 93 of the ring that contacts the furnace wall h h t retortand terminate hub 88 glazed and sealed with the furnace wall. 1 whlchthe collars 78 Y rotatable r313" The latter is preferably also glazed torender tlohv it impervious to gases. The glazing mateheat the retort 7lh h of spachd rial is any high temperature siliceous matehh h n l e mthe fhrhace rial having a low coeiiicient of expansion, and chamberextendmg circularly about h Y can be carried out in a manner well knownin tort. I .Heat may be supplied to the zones H]. ep y suitable t by ecombustion: of The lower part of the refractory ring 93 is fuel, orelect ically. These zones are m the 0pm2 to id 3 5 having opposite widthw h the p g y y to nozzles. 97. The latter discharge" premixed malhtelhy desued temPerCethTe g w as and air in' correct combining ratioHowever, regardless of the Specific m through the opposite portions 92aof the-said h t the Said zones, the Sa comprise ring. The said orificesmay constitute-parts radiant refractory areas that heat the retort f a il burner 98, To l th burner byradiation. \These areas are designed to beith th refractory ri'ng,'a strong hi h m Pa ticular y adapted f if rradiation perature cement 99 may be used, supported ,of heat, whetherthe heat be suppliedthereto on ablock 100 which rests on a plate 101.

the retortby internally fired devices outside peratures may be obtainedtherein. It will of the retort which, on becoming hot, probe appreciatedthat the rings constitute strucv'ide large masses of radiatingrefractory. tural shapes that can be efficiently, supported body, andnone of the gases of combustion by the furnace wall over alarge areaofthe needcome in contactwith the wall of the rerings.

To protect the orifices 97 against overheating, they may discharge intoconical spaces 102. These spaces serve to convey the gases at highvelocity to the surfaces 96. The

ring adjacent to the said surfaces may be thickened as shown at 103 toprovide sulfi-v cient interstitial area at the surfaces mentioned forrapldly receiving the gases without excessive resistance. An upperportion 104 10 of the ring is unglazed to provide an opening for theescape of the burnt gases.

The fuel is consumed in theintcrstices of the pieces of refractory 92,with flameless or surface combustion, the principles whereof are wellknown. It is intended that the mass of the refractory rings besufficiently great in proportion to the fuel consumed, that, after thefurnace has been thoroughly heat soaked and at equilibrium, thetemperature thereof be substantially uniform. It'will be evident tothose skilled in the art, that the said refractory rings can, ifnecessary, be modified to suit different operating condition? ,and yetcause the temperature thereof at 5 the lower portion of the retort to besubstan tially equal to that at the upper part thereof, regardless ofwhether this result he accomplished by providing a solid thick wallalong the said ring adjacent to the wall of the retort, or providing awall of this type of varying thickness.

WVith reference to surface combustion, it will suflice to briefly statethat the gaseous fuel is completely consumed with little or no excessoxygen. When the charge of gas and air is ignited in contact with thesurface of the refractory material, the heat developed is so intensethat the refractory becomes rapidly incandescent. Due to radiation ofheat from one piece of refractory to another, the entire mass of theporous refractory body becomes ultimately incandescent,'so that theentire ring becomes an efficient radiating medium. The glowlngrefractory material acts as a 5 catalyst and causes an almostinstantaneous combustion. The waste gases pass out through theinterstices of the refractory material at any suitable point in thering, and are utilized in heating the low temperature end of the retort.

0 bly fitted therein a hollow valve 112 having an opening 113 tocommunicate with the tube 110. Connected in any suitable manner to thevalve 112 isa coaxial Venturi tube 114 to pass the mixture of gasesintothe burner 98. Extending from the said valve is a spinor pulley1120. Thus a belt connection may serve to regulate from a central pointall of the said valves for the different combustion zones. Each valvemay be set at any desired predetermined position with respect to theother valves, and each pulley may be of a different size so that therate of opening or closing of the valves may be varied as amongthemselves.

After leaving the refractory rings, the gaseous products of combustionenter the openings 115 in the top wall of the furnace. These openingsare positioned between adjacent refractory rings, and communicate with aby pass 116 in the said Wall. This by pass permits the products ofcombustion to pass to the inlet end portion of the retort where they arecirculated spirally about the retort, since this portion of the furnaceis not provided with the refractory rings. Thus a temperature gradientisobtained which is desirable in the reduction of minerals. The spiraltravel of the gases may be obtained by. placin g spaced segmental plates117 and 118 at the top' and bottom of the furnace chamber between thewall thereof and the retort. To prevent short'circuiting of the gasesfrom the refractory rings to the spiral passages 119,

the retort'has a plurality of annular ribs or flanges 120 extending intocorresponding recesses 121 in the furnace wall; and a similar flange 122is provided at the inlet end of the retort to guard against leakage ofair into the furnace chamber and prevent oxidation of the retort. Fromthe spiral passages, the products of combustion enter an outlet 123.

To automatically regulate the temperatures and pressures in the retort,a central control 125 is provided. This includes thermocouples 126 and127, the former of which may extend into the compartment 59 of theretort, through the end plate 26, while the latter may be disposedexternally of the retort in proximity to the same compartment. A thirdthermocouple 128 is positioned outside of the retort adjacent to thewall of the retort compartment 57 Each of the thermocouples may beconnected to suitable induction coil and magnets 129, 130, and 131a,

respectively. The latter operate a control means, as, for example, thecorresponding valves 112 by any suitable means including levers 131connected to the pulleys 116. Induction coils and magnets 132 to 135 areprovided to control throttle valves 136 to 139 of the primer movers orvacuum pumps condevices 132 to 135 are connected in parallel.

The devices 129 to 131a may be in series with the circuit 140, 141 bymeans of wires 142,

and rheostats 143 may be provided forthe devices 129 to 131a. Powerlines 144 supply I electricity to the several devices. The rheostats areoperated by the induction magnets, and the relation of the two is suchthat the temperature pressure ratio may be kept constant, though one ofthese factors should accidently change.

In Fig. 14 is shown a modification of the invention, wherein the ringsare arranged to discharge the waste gases at a point where thetemperature of the gases has dropped sufficiently to be incapable ofimparting heat to the ring. Thus the ring 91a has openings or isunglazed at 916 intermediate of the upper and lower ends of the ring.The waste gases that-leavethe rings at 91?) enter recesses or passfiges24a in the wall of the furnace 24 and fiow upward exteriorly of therings into the outlet 116. The said passages 24a may be closed by therings themselves, and the waste gases will directly heat the upper sideportions 24?) of the furnace, reducing the loss of heat by conductionthrough the furnace walls, and afiording a high degree of uniformity inthe heating of the retort 21.

In Figs. 15 and 16 isshown a modified arrangement of the rings 91. Thisembodiment 145 is disposed circularly about. the heating chamber orretort 21, which it heats primarily by radiation, as above described,and may be similarly mounted within a furnace such as 24. It includes atubular refractory member 146, that has been suitably moulded and baked.The lower portion of the said member is enlarged to constitute anenclosure 147 which is analogous to a combustion chamber. Theupperportion of the member is in the nature of a ring 148 that conducts thehot products of combustion from the chamber 147 around the retort todischarge the same through an opening 149, whence they flow throughpassages 115 into the by pass 116 as'hereinbefore described. The chamber147 is open at its bottom at 150 to receive a hollow tile 151. Thelatter may be open at the bottom, but its upper closed end 152 is spacedfrom the inner wall 153 of the tubular member. Positioned in the saidtile 151 is a burner 154, having a plurality of oppositely extendingheads 155 lying in a plane at right angles to the axis of the tubularmember 145. Each of the heads has a plurality of small orifices todischarge the premixed air and fuel through openings 156 in the coactingopposite walls of the tile. To protect the burner, refractory blocks157,

- 158 are disposed thereabout, which also centrally position the same.Supporting the tile and also closing the bottom of the tubu; lar member145 is a refractory member 159 which rests upona plate 159a. Preferablycompletely filling the'tubular member 145 .is a porous refractorymaterial 160 that en closes the tile 151. This material may be in thenature of pieces of broken'refractory upon which the gas and air mixtureenter afterpassing through *the openings 156 in the tile to burnwithsurface combustion. The sizes of the pieces of refractory 160 ispredetermined to permit the required speed of travel of the products ofcombustion through the what thick, itmay be perforated as shown at 163to provide openings through which the incandescent refractory 160 maydirectly radiate-upon the retort. These radiant heat openings may alsovary in size to afiord uniform heating of the retort. It is noted thatthe bottom portion 164 of the inner wall 153 is imperforate to guardagainst any possibility of undue transmission of heat to the retort atthis point. That a portion of the products of combustion may be indirect contact with the retort may be of lesser importance since thematerial of the latter is well adapted to resist the action thereof. Asthe radiant heat acts between adjacent pieces of refractory in the ring,these pieces will all become incandescent ultimately, and thus affordthe main source of heat for the retort. To ignite the fuel, removableplugs 164a may be provided, accessible at the bottom of the furnace 24.

' In Fig. 17 is shown a modified arrangement of the heating rings, whichcan be practised with either form of ring hereinbefore described, andnow denoted as 165. These rings 165 are disposed along planes forming anacute angle with the retort, so that the effective heating zone of eachring is defined by its projected area 166. As the retort rotates a highdegree of uniformity of heating may be'obtained. The said rings may bearranged to space the projected areas, or the angle of inclination orwidths of the rin s may be varied-for the successive rings, to o tain a.temperature gradient.

In Figs. 18 and 19 is shown a modified rangement of a partition or wall167 for a lower portion of the disc, the same is provided with anopening or passage 17 5 laterally positioned according to the surface176 of the charge in the retort, that seals the said passage throughwhich the charge passes due to the slope of the retort. In making thepassage 175, an arcuate flange 177 may be formed to fill that portion ofthe groove adjacent to said passage.

In Figs. 20 and 21 is shown a further modificat-ion of the inventionwhich includes a partition or wall 1'. 8 and having a passage 179 forthe movement of charge that seals the same. A slight clearance may beobserved at 180 between the edge of the partition and the wall of theretort.

It will be appreciated that the partitions 55 are adapted for a variablecharge in the retort, while those shown at 167 and 178 require adefinite minimum charge to seal the passages therein. Furthermore, thepartitions 55 are adapted for a positive movement of the charge at anypredetermined speed.

In conclusion, it is desired to point out that considerable space hasbeen devoted herein to the exposition of various embodiments of theinvention, in order to obtain a clear, full, and'operative disclosure;but it is not desired to convey the impression that the means shown aresubstantiallyuthe only ones that can be used. Thus while heating membersof ring form have been shown, circular heating zones can be created inthe furnace by other means, or burners well known in the art. Further,the retort, the conveying means for the charge, and the partitions'canall be changed, separately, and collectively, within the scope of thebroad invention.

I claim:

1. An apparatus of the character described, including a chamber throughwhich the charge therein is adapted to move, means to heat the chamber.means to divide the chamber into a plurality of compartments to preventthe fiow of gases from one to another of said compartments and to causethe charge to move through the successive compartments, and positivemeans for forcibly exhausting the gases from the retort compartments.

2. A device of the character described, including a rotary heatingchamber, and relatively stationary means therein dividing the U sameinto a plurality of compartments and preventing a-free flow of gasesfrom one to another of the same, said chamber making an angle with thehorizontal to cause the charge to move therealong, said means having arestricted opening through which the charge passes in its movementaforesaid, and an annular series of pockets {rotating with the chamber,the pockets successively communieating with said opening inrelativelvclose relation thereto.

3. Adevice of the character described, in-

charge on the lower wall thereof,.said chamber having means thereinbelow its axis of rotation to receive a part of the charge,-said meanscoact-ing with the chamber to move therewith on rotation of the latterto a position above the said axis, and means coacting with the firstmentioned means for sealing the charge therein and causing the same tobe discharged back onto the lower wall at a point relatively in advanceof that at which the charge was received.

4.. A device'of the character "described, including a retort, means todivide the same into a plurality of compartments-and restrict the flowof gases between the compartments, and means to receive and enclosesuccessive batches of the charge to cause the'same to move from one toanother of the compartments past the first mentioned means.

5. A device of the character described, including a retort divided intoa plurality of compartments through which the charge is successivelymovable, means separately exhausting the gases from the compartments,and means heating the compartments to difjerent temperatures. v

6. A device of the character described, in-

cluding a plurality of compartments through which a charge issuccessively movable, means to heat the compartments at temperaturesthat increase from the first compartment to receive the charge, to thelast compartment, and means to exhaust from the compartments the gasestherein.

7. A device of the character described, including a retort divided intoa plurality of compartments through which the charge is successivelymovable, means separately exhausting the gases from the compartments,means heating the compartments to different temperatures, moval offinely divided material from the compartments with the exhausted gases.

8. A device of the character described, including a rotatable retort,means therein dividing the same into a plurality of succesand meanspreventing the re- 9. A device ofthe character described, in-

cluding a heating chamber having a plurality of compartments, means formoving the charge through the successive compartments, means to heat thecompartments to difi'erent temperatures, and means to separately removefrom the compartments the gases there- 10. A device of the clqracterdescribed, in-

. gas

eluding a heating chamber having a plurality of compartments, means forsuccessively compartments to different temperatures, and

means to separately remove the gases from i the compartments.

11.'A device of the character described, including heating means havinga plurality of compartments coacting for the movement of. the chargethrough said compartments, and means for maintaining different gaspressures in the difierent compartments.

12. A device of the character described, including a retort havingaplura'lity of compartments, said retort having means for moving thecharge successively through the compartments, and means for the separateremoval of the gases in the compartments.

13. A device of the character described, including a plurality of closedcompartmcnts, means for moving a charge through said compartments,heating means and gas exhausting means'for said compartments, separatecontrol means for the heating and exhausting means, and a unitary meansfor automatically regulating both control means.

14. A device of the character described, including a plurality ofcompartments, means for moving a charge through the compartments, meansto heat the compartments according to a temperature gradient for thecompartmentsithat increases in the direction of movement of the charge,and means to maintain a pressure gradient for the compartments thatdecreases in the direction of movement of the charge.

15. A device of the character described, in-. cluding a heating chamber,means to vary the temperature therein, means to vary the pressuretherein, and unitary means to automatically regulate the first andsecond mentioned means.

16. A device of the character described, including a closed heatingchamber, and means for controlling the temperature therein, m'eans forexhausting the gases therefrom,

means forcontrolling the exhausting means,

and other means for simultaneously operating both controlling means sothat an increase in temperature is accompanied by a decrease inpressure.

17 A device for the reduction of pulverized ores, mixed-with coal,including a rel tort, means for heating the retort from the outside,continuously fed through the retort, and means for forcibly exhaustingfrom the retort the gases therein, the exhausting means ineludingseparate tubular elements communicating with different parts of theretort for separately withdrawing the gases from the zones inwhichtheyare generated.

means, for causing a charge to be 18. A device for the reduction ofpulverized ores, including a closed retort, means for heating the samefrom the outside, the retort having means for continuously feeding acharge therethrough, means for forcibly continuously exhausting thegases in the retortand to produce a decreased pressure therein, andmeans coacting with the exhausting means to prevent the removal offinely divided solid materials with the exhausted gases.

19. A eluding a retort, the same having means ,for continuously feedinga charge therethrough, means for externally heating the retort accordingto a temperature gradient, and means for forcibly separately withdrawingthe gases in the retort from the different-respective zones therein inwhich the gases are generated.

20. A device including an elongated retort, and means for heating thesame from the outside, said means including a plurality of thin walled,internally fired elements extending around the retort for radiating heatthereon, said elements being of varying width with respect to each otherfor maintaining a temperature gradient in the retort.

device for the reduction of ores'in-

